Image Processing Technology Performing Designated Processing on Normal Orthogonally Transformed Images

1. An image processing apparatus that performs designated processing on an image for which high frequency components have been removed, said image processing apparatus comprising: a memory unit configured to store a predetermined designated noise; a noise adding unit configured to receive the predetermined designated noise from the memory unit and configured to add the predetermined designated noise to the image with said high frequency components removed, wherein the predetermined designated noise is generated by discrete cosine transformation of a dither matrix.

2. A computer program product that causes a computer to perform designated processes on a normal orthogonally transformed image, said computer program product comprising: a first program code that causes said computer to add non-random designated noise to said image that has undergone said normal orthogonal transformation; a second program code that causes said computer to perform a reverse normal orthogonal transformation, which is a reverse transformation of said normal orthogonal transformation, on said noise-added image; a third program code that causes said computer to binarize said image, which has undergone said reverse normal orthogonal transformation, using a designated threshold value; and a computer readable medium, in which said first program code, said second program code, and said third program code are stored.

3. The computer program product of claim 2 , wherein the first program code further causes the computer to generate the non-random designated noise based on a dither matrix.

4. The computer program product of claim 2 , wherein the first program code further causes the computer to retrieve the non-random designated noise from a memory unit.